Absorbent articles and structures, such as absorbent pads and absorbent cores, have been formed by employing various techniques, such as wet forming techniques, and air laying techniques. Conventional air laying techniques have transported a foraminous forming surface, such as a forming screen, through a forming chamber. Fibrous materials and particulate materials have been introduced into the forming chamber, and a vacuum source has been employed to draw an air stream through the forming surface. The air stream entrains the fibers and particulate material for deposition onto the moving forming surface. In particular systems, a nozzle has been employed to deliver and direct the particulate material into the forming chamber, and the particles have been composed of superabsorbent material.
Multiple forming chambers have been employed to form different layers of material in a composite absorbent article. The different layers have included different types of particulate material, and have been composed of different types of fibrous material.
Such conventional techniques have been excessively complex and costly, especially those that employ multiple forming chambers. In addition, such conventional techniques have not adequately regulated the delivery of particles, such as superabsorbent particles, into desired locations within a fibrous web. More particularly, the conventional techniques have not adequately provided the deposition of particles into desired locations along a thickness dimension of the fibrous web. Also, the conventional delivery nozzles have not adequately provided the desired distributions and concentrations of the particulate material within the fibrous web. For example, the conventional delivery nozzles have not adequately generated desired, superabsorbent-rich strata within a selected absorbent article. As a result, there has been a continued need for improved techniques for controlling the deposition of particulate material in desired strata of a fibrous web, and for generating desired superabsorbent-containing strata within a composite absorbent article.